mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 13:42:02 +00:00
62 lines
1.7 KiB
C++
62 lines
1.7 KiB
C++
#pragma once
|
|
|
|
#include <Core/Types.h>
|
|
#include <Parsers/IAST_fwd.h>
|
|
#include <Storages/IStorage_fwd.h>
|
|
|
|
#include <string>
|
|
#include <memory>
|
|
|
|
|
|
namespace DB
|
|
{
|
|
|
|
class ASTSelectQuery;
|
|
class Context;
|
|
|
|
|
|
/** Scheme of operation:
|
|
*
|
|
* If "main" table in a query is distributed enough (thus, have at least two shards),
|
|
* and there are non-GLOBAL subqueries in IN or JOIN,
|
|
* and in that subqueries, there is a table
|
|
* (in any nesting level in that subquery or in more deep subqueries),
|
|
* that exist on local server and (according to information on local server) is also distributed enough
|
|
* then, according to setting 'distributed_product_mode',
|
|
* either
|
|
* - throw an exception;
|
|
* - or add GLOBAL to top subquery;
|
|
* - or replace database and table name in subquery to remote database and table name,
|
|
* as Distributed storage on local server knows it.
|
|
*
|
|
* Do not recursively preprocess subqueries, as it will be done by calling code.
|
|
*/
|
|
|
|
class InJoinSubqueriesPreprocessor
|
|
{
|
|
public:
|
|
struct CheckShardsAndTables
|
|
{
|
|
using Ptr = std::unique_ptr<CheckShardsAndTables>;
|
|
|
|
/// These methods could be overriden for the need of the unit test.
|
|
virtual bool hasAtLeastTwoShards(const IStorage & table) const;
|
|
virtual std::pair<std::string, std::string> getRemoteDatabaseAndTableName(const IStorage & table) const;
|
|
virtual ~CheckShardsAndTables() {}
|
|
};
|
|
|
|
InJoinSubqueriesPreprocessor(const Context & context_, CheckShardsAndTables::Ptr _checker = std::make_unique<CheckShardsAndTables>())
|
|
: context(context_)
|
|
, checker(std::move(_checker))
|
|
{}
|
|
|
|
void visit(ASTPtr & query) const;
|
|
|
|
private:
|
|
const Context & context;
|
|
CheckShardsAndTables::Ptr checker;
|
|
};
|
|
|
|
|
|
}
|